Let's start with subordinate closed interrogative clauses, since I think in Vietnamese, they work pretty much the same way as in English:

• If Bertha accepted that offer, she's crazy.

Translation:

Nếu Bertha đồng ý lời đề nghị đó, cô ấy thật là điên rồ.

Funny thing is, as you can see, you can translate the English sentence above into Vietnamese word-by-word, and the word order still stays the same. Note that I'm not using the particle "đã" (which is sometimes used to indicate past tense) before "đồng ý", since it sounds really awkward in this context (in fact, most of the time, if not almost always we wouldn't use it.)

• I don't know if Bertha accepted that offer.

Translation:

Tôi không biết Bertha có chấp nhận lời đề nghị đó hay không/chưa..

So in Vietnamese, if you put the conditional clause (that is "if Bertha accepted that offer" in this case) behind the main clause (I don't know/I'm not sure/I don't care, etc.), you remove "nếu" (which means "if" in English). And then you have to add "hay không" or "hay chưa" (which is literally translated as "or not" in English) at the end of the sentence, because without them, it would sound really odd and more likely nobody would understand what you mean.

In Vietnamese, there are no inversions used in conditional sentences, so we don't use something like "Should you see Bob, tell him to phone me" and such... like in English. Only "If" works! -> "If you see Bob, tell him to phone me"

Let's move on to main clause open interrogatives!

Whoever would agree to that?

Translation:

Ai mà đồng ý với điều đó?

But to express the idea of "Whoever would agree to that, Bob won't.". You can NOT just copy-paste the translation above and make it like: "Ai mà đồng ý với điều đó, Bob thì không đâu" NO! You should use this instead:

Ai đồng ý thì đồng ý, Bob thì không đâu.

Let's start with subordinate closed interrogative clauses, since I think in Vietnamese, they work pretty much the same way as in English:

• If Bertha accepted that offer, she's crazy.

Translation:

Nếu Bertha đồng ý lời đề nghị đó, cô ấy thật là điên rồ.

Funny thing is, as you can see, you can translate the English sentence above into Vietnamese word-by-word, and the word order still stays the same. Note that I'm not using the particle "đã" (which is sometimes used to indicate past tense) before "đồng ý", since it sounds really awkward in this context (in fact, most of the time, if not almost always we wouldn't use it.)

• I don't know if Bertha accepted that offer.

Translation:

Tôi không biết Bertha có chấp nhận lời đề nghị đó hay không/chưa..

So in Vietnamese, if you put the conditional clause (that is "if Bertha accepted that offer" in this case) behind the main clause (I don't know/I'm not sure/I don't care, etc.), you will need to remove "nếu" (which means "if" in English). And then you have to add "hay không" or "hay chưa" (which is literally translated as "or not" in English) at the end of the sentence, because without them, it would sound really odd and more likely nobody would understand what you mean.

In Vietnamese, there are no inversions used in conditional sentences, so we don't use something like "Should you see Bob, tell him to phone me" and such... like in English. Only "If" works! -> "If you see Bob, tell him to phone me"

Let's move on to main clause open interrogatives!

Whoever would agree to that?

Translation:

Ai mà đồng ý với điều đó?

But to express the idea of "Whoever would agree to that, Bob won't.". You can NOT just copy-paste the translation above and make it like: "Ai mà đồng ý với điều đó, Bob thì không đâu" NO! You should use this instead:

Ai đồng ý thì đồng ý, Bob thì không đâu.